Abstract: A composite wire useful for arc gun spraying is formed of an alloy sheath comprising iron, nickel, or cobalt, and a core comprising boron-containing powder of boron and/or boron carbide sufficiently fine in size such that the boron is substantially dissolved in a coating produced by arc gun spraying the composite wire. Where the boron substance includes boron, the core should further comprise fine carbon powder less than 20 microns in size blended with the boron powder. Preferably a substantial portion of the boron-containing powder is less than 20 microns. In a particularly desirable embodiment, the sheath is formed of mild steel and the core comprises boron carbide and an alloy powder such as ferromolybdenum.

Abstract: A flame sprayable powder composition suitable for coating a plastic substrate comprising by weight (a) about 90 to 98% of a flame sprayable mineral powder, (b) about 1 to 5% of a nylon powder, and (c) about 1 to 5% of an epoxy resin powder. The coated plastic may thereafter be overcoated by flame spraying with conventional metal or ceramic powders. The undercoat results in a good bond to the substrate.